Most translation projects result in a document that is longer than the English source. You must plan for text expansion, or occasionally contraction, during the creation of the source material. This phenomenon impacts the layout differently in each language. While actual expansion percentages vary based on the content area and the translator’s writing style, we use the following general ranges to help you plan your document or interface layouts.
Many languages translated from English, including Spanish, French, Italian, Portuguese, Polish, Arabic, and Hebrew, will result in text expansion of 15% to 30%. A few languages, such as Dutch and German, may expand by 35% or even higher. For example, a simple button label like "Submit" (6 letters) can become "Absenden" (8 letters) in German, which immediately impacts your UI design.
Chinese, Japanese, and Korean will generally contract in character count, although the percentages vary widely from -10% to -55%. However, you may still encounter character expansion, where the text requires increased space between characters or uses complex character styles. This means that the horizontal space required to fit the translated characters could remain the same or even expand beyond the source. You might also face vertical expansion, or an increase in character height. Consequently, the spacing between lines of text may need to be greater than in the original document.
In modern software development, hard string limits often clash with linguistic reality. These specific constraints require careful planning.
String Limits & Pseudo-Translation: Designers often place hard limits on strings to preserve the integrity of a UI. Setting requirements at the exact length of the English source is a mistake that leads to truncated text. We recommend using pseudo-translation (translating with dummy text and an expansion factor) to test how the build works before live translation begins.
Abbreviations: Be careful when abbreviating text to fit into small spaces. It might not be possible to replicate such abbreviations in other languages. Translators may need to write the terms out in full to avoid losing meaning.
Short Source Text & Navigation: Sometimes very short source text results in higher-than-expected expansion. For example, "FAQ" translates to "Preguntas frecuentes" in Spanish. Using acronyms poses a significant challenge in space-restricted areas like tabs, mobile navigation bars, or buttons.
Compound Nouns: The use of long compound nouns creates single words that replace a sequence of smaller words in the source, often resulting in awkward text wrapping. Where the English might easily wrap to two lines, German, Finnish, and Dutch may contain longer words that pose a challenge for automatic text wrapping.
Try to design your document with as much flexibility as possible to allow for text re-flow. Whenever possible, avoid small, fixed-width headers, tabs, buttons, or graphics. This approach will not only keep your desktop publishing costs down but will also avoid awkward translations. It simplifies the QA process and ultimately reduces project turnaround.